Jun 1 2009
Abraxis BioScience, Inc. (NASDAQ:ABII), a fully integrated global biotechnology company dedicated to the discovery, development and delivery of next-generation therapeutics and core technologies that offer patients safer and more effective treatments for cancer and other critical illnesses, today announced results from a new ongoing study demonstrating anti-tumor activity for three dosing regimens of nab®-paclitaxel (ABRAXANE® for Injectable Suspension) (paclitaxel protein-bound particles for injectable suspension) (albumin-bound) given in combination with bevacizumab in the first-line treatment of patients with metastatic breast cancer.
The overall response rate for patients receiving a combination of weekly nab-paclitaxel (130 mg/m2) with twice weekly bevacizumab (10 mg/kg) was 46 percent. Patients who received a combination of nab-paclitaxel (260 mg/m2) with bevacizumab (10 mg/kg) plus filgrastim administered every two weeks and patients who received nab-paclitaxel (260 mg/m2) with bevacizumab (15 mg/kg) administered every three weeks had overall response rates of 39 percent and 44 percent, respectively. The safety profile was generally consistent with the known safety of nab-paclitaxel and of bevacizumab, although sensory neuropathy was limiting in the weekly nab-paclitaxel dosing arm suggesting a three week on treatment, one week off treatment regimen may be preferable.
Results also demonstrated a prolonged time to progression (9.0 months) among patients who received weekly nab-paclitaxel, compared to the every two and three week dosing regimens (6.3 months and 7.7 months, respectively). Overall survival data has not yet been established, and is currently being evaluated. Findings were discussed during an oral presentation (Abstract #1006) on June 1 at the 45th Annual Meeting of the American Society of Clinical Oncology (ASCO) being held in Orlando, Fla.
"This study was initiated to expand on previous findings, such as the pivotal ECOG 2100 trial, demonstrating the benefit of Cremophor®-based paclitaxel given in combination with bevacizumab in the treatment of patients with advanced breast cancer," said study lead investigator Andrew D. Seidman, M.D., Attending Physician, Breast Cancer Medicine Service, Memorial Sloan-Kettering Cancer Center. "Further evaluation of nab-paclitaxel given weekly for three weeks followed by one week off treatment is ongoing in the CALGB 40502 trial. This Phase III study will help us better define a role for the combination of nab-paclitaxel and bevacizumab as a first-line treatment option for metastatic breast cancer."
Nab-paclitaxel is currently approved for the treatment of breast cancer after failure of combination chemotherapy for metastatic disease or relapse within six months of adjuvant chemotherapy. Prior therapy should have included an anthracycline unless clinically contraindicated.
The open-label, Phase II study evaluated nab-paclitaxel in three dosing regimens in combination with bevacizumab, including:
* nab-paclitaxel (260 mg/m2) given every three weeks in combination with bevacizumab (15 mg/kg) every three weeks;
* nab-paclitaxel (260 mg/m2) given every two weeks in combination with bevacizumab (10 mg/kg) every two weeks plus filgrastim; and
* nab-paclitaxel (130 mg/m2) given every week for three weeks plus bevacizumab (10 mg/kg) given every two weeks.
About the Study
Randomized phase II trial of nanoparticle albumin-bound paclitaxel in three dosing schedules with bevacizumab as first-line therapy for HER2-negative metastatic breast cancer (MBC) (Abstract #1006)
In the randomized Phase II, open-label study, patients had HER-2 negative metastatic breast cancer and no prior chemotherapy treatment in the metastatic setting. The primary endpoints were safety and tolerability and overall response rate (defined as confirmed complete and partial responses according to RECIST criteria). Secondary study endpoints include time to progression and overall survival. Of the 209 patients randomized, 205 patients with similar patient demographics and baseline characteristics were treated. Seventy-three patients were treated with nab-paclitaxel in combination with bevacizumab every three weeks, 54 patients every two weeks (plus filgrastim) and 78 patients weekly. The majority of patients in all treatment arms had visceral disease (88 percent, 92 percent and 87 percent of patients for the three treatment arms, respectively) and received prior neoadjuvant or adjuvant chemotherapy (63 percent, 61 percent and 61 percent for the three treatment arms, respectively).
Overall, the combination of nab-paclitaxel and bevacizumab was well-tolerated and grade 2, 3 and 4 neurotoxicities were comparable across all three dosing regimens, with febrile neutropenia occurring in less than 2 percent of patients in all study arms. Grade 3-4 toxicities occurring in at least one patient in each treatment arm included: sensory neuropathy (30 percent for the nab-paclitaxel every three weeks arm, 48 percent for the nab-paclitaxel every two weeks arm and 40 percent for the weekly nab-paclitaxel arm); fatigue (15 percent, 30 percent and 14 percent for the three treatment arms, respectively); nausea (4 percent, 6 percent and 0 percent, respectively); and diarrhea (0 percent, 2 percent and 4 percent, respectively). Patients taking nab-paclitaxel (130 mg/m2) on a weekly dosing regimen in combination with bevacizumab (10 mg/kg) experienced significantly less grade 2-3 arthralgia, myalgia and nausea, compared to the every two and three week dosing regimens. The every two week dosing arm crossed an early stopping rule because of excess toxicity and was closed early. Results suggest a three week on treatment, one week off treatment regimen may be preferable.